In a piece for the Guardian this week, Kate Hodal and Chris Kelly share the story of Myint Thein, a Burmese fisherman who spent two years as a slave on a boat in Thailand. Like many trafficked persons, Thein migrated voluntarily: he paid a middleman to smuggle him across the border into Thailand and find him a job in a factory. It was only when he reached Thailand that Thein realized he had been sold to a boat captain.

While the phrase “human trafficking” is often used synonymously with “sex trafficking,” Thein’s story is an important reminder of the varied experiences and struggles of trafficked persons and how American companies can enable this horrific practice. These Thai vessels catch shrimp for CP Foods, an international company that in turn supplies food retailers and international supermarkets, including Walmart and Costco.

Phil Robertson, deputy director of Human Rights Watch’s Asia Division, described to Hodal and Kelly the “systematic” use of trafficked labor in the Thai fishing industry, describing a “predatory relationship” between migrant workers and boat captains. Thai border police often play a key role in these transactions, accepting bribes to turn a blind eye or even directly aid traffickers. According to the Global Slavery Index, nearly 500,000 people are believed to be enslaved in Thailand.

Hodal and Kelly describe the horrible conditions on Thai fishing boats, where approximately 300,000 migrants work, often for 18 to 22 hours a day. Reports of torture and murder of fisherman on these boats are widespread, with one fisherman claiming to have seen 18 to 20 people killed by his captain.

Facing increasing international pressure, the Thai government says that it is doing its best to inhibit trafficking operations by increasing prosecutions. But experts say that little change has taken place and emphasize the important role of international retailers. As Thai border police continue to turn a blind eye to this tragedy, international retailers need to show that ignorance is not an option when it comes to human lives.

“If local businesses realize that noncompliance results in loss of business and competitiveness, and that these brands and retailers will indeed reconsider their sourcing practices throughout their supply chain, it has the potential to bring about huge positive change in the lives of migrant workers and trafficking victims,” Lisa Rende Taylor, of Anti-Slavery International, told the Guardian.